The present invention relates to a plow system; and more particularly, it relates to a plow system with a number of individual plow units mounted to a main frame for adjustment about their respective vertical axes. This adjustment permits the units to be "opened" or "closed" by an operator from the traction vehicle pulling the plow system, without leaving his position and while continuing to operate the vehicle. Such a system is disclosed in my U.S. Pat. No. 3,817,333, granted June 18, 1974. Another multi-bottom plow system is disclosed in the Thompson U.S. Pat. No. 3,559,745, but this latter is directed to a system in which the plow units may be shifted either full-right or full-left, depending upon whether the operator wants to plow with the newly-plowed ground on his right or on his left.
In early commercial multi-unit plow systems, the number of plow units or bottoms has been limited generally in the range of five or six units mounted on a single, rigid frame. There has been no need of adding additional units because the limiting factor has been the draw power of the traction vehicle, particularly when the plow units are set for plowing at deeper levels.
More powerful tractors are now readily commercially available; but if one simply extends the concept in my above-identified patent by adding plow units to a single rigid beam, the length of that beam may be as long as 32 or 33 feet for a system with 10 plow units, and correspondingly longer for a system with 14 plow units, of course. Such a large system is difficult to support. Further, there are problems in providing the flexibility that such a system should have, both during plowing over the various range of lateral settings for the plow bottoms, and for the various maneuvers required during plowing. Still further, there is the problem of following the contour of the land with a very long, rigid main beam extending over 30 feet.
Briefly, the present invention provides a main articulated frame including a forward frame section with an inclined main beam, and a rear frame section with an inclined main beam. A first plurality of plow units or bottoms are pivotally mounted for rotation about vertical axes on the forward frame section, and a second plurality of plow units are similarly mounted on the rear frame section. The forward frame section and the rear frame section are mounted together for rotation about a horizontal axis extending generally transverse to the direction of vehicle travel, thereby articulating the forward and rear frame sections relative to each other, and permitting them to independently follow the contour of the ground. This is important because when a farmer sets the system for plowing at a given depth, he wants all of the units plowing at that depth, and variations of even an inch or so are undesirable. Depending upon the curvature of the ground, much greater variations would occur if a main beam having a length of over 30 feet were rigid and not permitted to follow the contour of the ground.
A guide beam or tie rod interconnects all of the individual plow units, both on the forward frame section and the rear frame section so that they are all rotated in unison. Rotation of the plow units is effected by means of a hydraulic cylinder unit and linkage assembly on the forward frame section, the linkage being interconnected between an individual plow unit and a tongue or draft member which is pivotally connected to the tractor and pivotally connected to the forward frame section at a location toward the rear of that section.
For supporting the system, in addition to the weight borne by the tractor hitch, there are three support wheels: a first caster wheel located at the front of the unit and to the right of the rear tractor wheel for riding in a previously-cut furrow; a rear caster wheel for following in the furrow cut by the last plow unit; and an intermediate wheel which rides on unplowed ground and is steered as a function of the adjusted width of the individual plow units. Three additional hydraulic cylinders are provided, one for each of the support wheels for selectively raising and lowering the system, not only to adjust plowing depth, but to raise all of the units out of the ground to provide sufficient clearance for road travel.
Thus, the present invention provides a plow system which is capable of accommodating as many as 14 individual plow units while adjusting all of the units in unison, and which is capable of following the contour of the ground being plowed for all of the various width adjustment settings.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.